It is known to use an artery graft (e.g., internal thoracic artery, gastroepiploic artery and radial artery) or a vein graft (e.g., great saphenous vein) as a bypass vessel in performing vascular bypass grafting at the heart (coronary artery bypass grafting: CABG). It has been reported that. at present, artery grafts (particularly, internal thoracic artery) offer higher long-term patency rates than vein grafts. Vein grafts are commonly thought to be poor in long-term patency rate. In recent years, however, it has been reported that the long-term patency rate of vein grafts is enhanced when the vein graft is harvested in a state in which the vein is covered by surrounding tissue (for example, fat, connective tissue, tissue between a skin layer and a muscle layer, tissue between a skin layer and an interosseous membrane, branch vessels, etc.) and is used as a bypass vessel while remaining covered with the tissue.
Generally speaking, there are two primary techniques for harvesting blood vessels such as the saphenous vein. One technique is referred to as open vein harvesting. This technique involves making an elongated incision along, for example, the patient's limb (leg), and then carrying out the harvesting procedure for removing the blood vessel from the patient's limb. This technique has been found to be somewhat problematic in that it is rather invasive, requiring a rather extensive incision in the patient's limb. Harvesting site complications (e.g., infections) are also not uncommon.
Another technique is referred to as endoscopic vein harvesting. This technique has some advantages over open vein harvesting in that the endoscopic vein harvesting is less invasive and has been found to have a lower incidence of infection. Unfortunately, endoscopic vein harvesting exhibits a lower patency rate because the harvested vein tends to be more damaged.